3. Development prospects for new techniques – Thermochromic coatings

3.1 Context

A thermochromic coating changes color with temperature, and this property is reversible. The etymology of the word thermochromic comes from the Greek thermos (temperature) and chromos (color). This characteristic has been explored for several years in terms of passive radiative cooling of buildings. The aim is to sharply reduce the solar radiation absorption coefficient of buildings' exterior surfaces, while significantly increasing their emissivity, particularly in the "atmospheric window" (far infrared). In some cases, this can result in a lower external surface temperature than the air temperature, which also helps reduce the urban heat island phenomenon. What's more, the albedo of the cladding can vary, with a dark color in winter (low temperature) to absorb solar radiation,...